Revert of [heap] Introduce parallel compaction algorithm.

src/heap/mark-compact.h

Index: src/heap/mark-compact.h
diff --git a/src/heap/mark-compact.h b/src/heap/mark-compact.h
index 714ad16bc8b3005bb31649aa6a17fea3ac7ea6f9..e0b7c38ca0bd0cfc2c0f785b31c59c476a576943 100644
--- a/src/heap/mark-compact.h
+++ b/src/heap/mark-compact.h
@@ -553,11 +553,8 @@
   // Synchronize sweeper threads.
   base::Semaphore pending_sweeper_jobs_semaphore_;
 
-  // Synchronize compaction tasks.
-  base::Semaphore pending_compaction_tasks_semaphore_;
-
-  // Number of active compaction tasks (including main thread).
-  intptr_t concurrent_compaction_tasks_active_;
+  // Synchronize compaction threads.
+  base::Semaphore pending_compaction_jobs_semaphore_;
 
   bool evacuation_;
 
@@ -715,16 +712,11 @@
 
   void EvacuateNewSpace();
 
-  bool EvacuateLiveObjectsFromPage(Page* p, PagedSpace* target_space);
-
-  void EvacuatePages(CompactionSpaceCollection* compaction_spaces);
+  void EvacuateLiveObjectsFromPage(Page* p, PagedSpace* target_space);
+
+  void EvacuatePages();
+
   void EvacuatePagesInParallel();
-
-  int NumberOfParallelCompactionTasks() {
-    // TODO(hpayer, mlippautz): Figure out some logic to determine the number
-    // of compaction tasks.
-    return 1;
-  }
 
   void WaitUntilCompactionCompleted();